Insects use thousands of individual lenses that work together to provide a wealth of input.
The lenses could be used for three-dimensional imaging, as they produce sets of images with different focal lengths, ranging from a few micrometres to a few tens of micrometres. The lenses are reconfigurable with temperature and sensitive to light polarisation – the latter thought to be one of the ways bees navigate..
The research was published in Advanced Optical Materials.
Previous work by the group had shown how smectic liquid crystal, a transparent, soap-like class of the material, naturally self-assembled into flower-like structures when placed around a central silica bead. Each “petal” of these flowers is a “focal conic domain,” a structure that other researchers had shown could be used as a simple lens.
“Given the liquid crystal flower’s outward similarity to a compound lens, we were curious about its optical properties,” says study co-leader Mohamed Amine Gharbi, a postdoctoral researcher in the physics and astronomy department
The researchers made the lenses using photolithography to create a sheet of micropillars, then spread the liquid crystal on the sheet.
At room temperature, the liquid crystal adheres to the top edges of the posts, transmitting an elastic energy cue that causes the crystal’s focal conic domains to line up in concentric circles around the posts
